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Medium 4.3Published Sep 25, 2026

CVE-2026-6103Phar TAR phar_tar_number() Integer Overflow - Archive Entry Injection

Updated under an hour ago ()

Does this affect you?

It affects PHP Group PHP. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

phar_tar_number() parses the octal size field of a TAR header into a uint32_t with no overflow check. The field is 11 octal digits wide and holds values up to 0x1FFFFFFFF, so a size above 0xFFFFFFFF silently wraps. The parser then skips the wrong number of data blocks and interprets attacker-controlled file content as the next TAR header, which lets a crafted archive inject entries that PharData reports and extracts as if they were genuine.

CVSS
4.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Weakness (CWE)
CWE-190
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
php
NVD analysis
Awaiting Analysis
Record last updated
Sep 25, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
PHP Group PHP
php_group:php (from the name)
from 8.2.* before 8.2.34; from 8.3.* before 8.3.35; from 8.4.* before 8.4.26; from 8.5.* before 8.5.11
CNA record

References

  • vendor-advisory

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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